Table 1.

Regression models to relate excavated root counts of trees in two pavement treatments as compared to ground penetrating radar counts of root signals. As a ground-truth verification study, the expected slope would be equal to 1 (one root for each signal) with an intercept of zero. In the regression models presented, y = excavated root count, and x = GPR count.

ModelEquationnS.E. slopep-value Ho slope = 1.0S. E. constantp-value Ho constant = 0r2
Experiment-wide (mixed effect model)y = 0.84x + 0.26800.050.004  0.360.47650.88
CU-Soil
    scan sectiony = 0.83x + 0.97400.070.022  0.460.4350.81
    treey = 0.96x + 3.8  50.230.8710.210.7350.86
Silt loam
    scan sectiony = 0.77x − 0.12400.090.017  0.430.78460.76
    treey = 2.13x − 40.6  50.950.3026.10.2170.63